The invention relates to a control system for a longwall support with a plurality of hydraulically actuated supports (mining shields).
A longwall control system of this type is known from DE P42 02 246.0. In this system, the mining shields are adapted for automatic rearrangement in the sense of robbing, advancing, and setting as a function of the position of the mining machine (coal cutters or plows). To this end, the position of the mining machine is automatically signaled to the mining shield control system via a double pulse generator and a trailing cable that is pulled along by the mining machine. This control system has the disadvantage that the layout of such a cable is expensive and subjected to the risk of damage and considerable wear. This again results in hazards for the safe support of the longwall by false messages and incorrect controls.
It is accordingly an object of the present invention to provide an improved control system for a longwall support.
The above and other objects and advantages of the present invention are achieved by the provision of control system for a longwall support having a plurality of hydraulically operated supports that are automatically arranged via a mining shield control system in the sense of robbing, advancing, and setting as a function of the position of a mining machine that travels along and removes rock from the longwall. The control system comprises a position signaler that is carried by the mining machine. The position signaler comprises a rotatable measuring wheel that rotates in response to the mining machine traveling along the longwall and comprises electromagnetically detectable circumferential markings. For example, the rotatable measuring wheel can be a pinion. The position signaler further comprises a detector for sensing the electromagnetically detectable circumferential markings and providing a signal derived from the sensing. More specifically, the detector can be two inductive pulse generators (a double pulse generator), which scan or scans the electromagnetically detectable circumferential markings. The position signaler further comprises a microprocessor for receiving the signal from the detector and converting the signal into a processed signal, namely position signals and/or signals of the direction of movement. The position signaler further comprises a radio transmitter for transmitting the processed signal to the mining shield control system for use in the automatic arrangement of the hydraulically operated supports. The mining shield control system comprises one or more radio receivers that are distributed along the length of the longwall for receiving the transmitted processed signal from the position signaler. The mining shield control system converts the processed signal received by the radio receiver(s) into signals for rearranging the hydraulically operated supports.